Print Email Facebook Twitter Statistically optimal estimation of surface mass anomalies by directly using GRACE level-2 spherical harmonic coefficients as measurements Title Statistically optimal estimation of surface mass anomalies by directly using GRACE level-2 spherical harmonic coefficients as measurements Author Chang, Guobin (Xi’an Research Institute of Surveying and Mapping; China University of Geosciences) Qian, N. (TU Delft Physical and Space Geodesy; China University of Mining and Technology) Bian, Shaofeng (China University of Geosciences) Date 2023 Abstract Point-mass inversion is widely employed in GRACE level-2 data processing. Conventionally, the spherical harmonic (SH) coefficients are used indirectly: a set of pseudo measurements is generated first using the SH coefficients through SH synthesis; then the point-mass inversion is done with these pseudo measurements. To be statistically optimal, the covariance matrix of pseudo measurements should be calculated and used to appropriately weigh the parameter estimation. In this work, we propose a statistically optimal point-mass inversion scheme by directly using the SH coefficients as measurements. We prove the equivalence between this direct approach and the conventional indirect approaches. We also demonstrated their comparable performance through both simulation and real GRACE data processing. Choosing and calculating pseudo measurements, propagating covariance matrix, and potentially dealing with the singularity of the covariance matrix involved in the conventional indirect approaches are avoided in the proposed direct approach. This statistically optimal direct approach can readily be employed in mascon inversion of GRACE data and other radial basis functions-based approaches in regional gravity modeling. Subject Global change from geodesyGRACEMass anomalySatellite gravityTime variable gravity To reference this document use: http://resolver.tudelft.nl/uuid:4cd3325b-aff6-40c8-8d9c-dd1d2f36a235 DOI https://doi.org/10.1093/gji/ggad024 Embargo date 2023-07-23 ISSN 0956-540X Source Geophysical Journal International, 233 (3), 1786–1799 Bibliographical note Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public. Part of collection Institutional Repository Document type journal article Rights © 2023 Guobin Chang, N. Qian, Shaofeng Bian Files PDF ggad024.pdf 16.91 MB Close viewer /islandora/object/uuid:4cd3325b-aff6-40c8-8d9c-dd1d2f36a235/datastream/OBJ/view